1. Field of the Invention
The present invention relates to an input device (touch panel which is used in combination with a liquid crystal display or the like, and a method of manufacturing the same.
2. Description of the Related Art
As described in Japanese Unexamined Patent Application Publication No. 2009-301767, a touch panel includes a transparent surface panel (transparent substrate 23), a decorative layer (light-shielding layer 24) which is formed in a decorative region below the surface panel, a transparent planarizing layer (overcoat layer 25) which is formed over the entire region of the lower surfaces of the surface panel and the decorative layer, and transparent electrodes (transparent conductive layer 26) which are formed in the lower surface of the planarizing layer, and the like.
In Japanese Unexamined Patent Application Publication No. 2009-301767, transparent resin, such as photosensitive acrylic resin is spin-coated to form the planarizing layer.
However, in the configuration in which the planarizing layer is formed of a resin layer by spin coating, in particular, the degree of planarization of the planarizing layer is degraded due to a step between the surface panel and the decorative layer, or the like. For this reason, there is a problem in that the transparent electrodes may not be formed on the planarized surface, causing deterioration in sensor sensitivity.
In Japanese Unexamined Patent Application Publication No. 2009-301767, since a planarizing layer is necessary, the touch panel increases in thickness, and there is a problem in that it is difficult to appropriately achieve a reduction in thickness.
A process for manufacturing a touch panel of the related art includes printing of a decorative layer printing, deposition of transparent electrodes, such as ITO (Indium Tin Oxide), pattern formation by photolithography, and bonding of base materials. In this way, a plurality of complex manufacturing process techniques are required, leading to an increase in instrument investment cost or process technique development cost. Accordingly, the manufacturing process is extended, causing deterioration in productivity.
In a touch panel described in Japanese Unexamined Patent Application Publication No. 2009-193587, a decorative layer (mask layer 12), a planarizing layer (smoothing layer 15), and transparent electrodes (sensing circuit 13) are laminated in a decorative region below a surface panel (single substrate 11). Accordingly, there are the same problems as those in Japanese Unexamined Patent Application Publication No. 2009-301767.